Place the bulghur in a large bowl, pour in the boiling water, and add the lemon juice, olive oil, and 1 1/2 teaspoons salt. Stir, then allow to stand at room temperature for about 1 hour.

Add the scallions, mint, parsley, cucumber, tomatoes, 2 teaspoons salt, and the pepper; mix well. Season, to taste, and serve or cover and refrigerate. The flavor will improve if the tabbouleh sits for a few hours.